Poussey's Mom is the deceased mother of Poussey Washington. She passed away whilst Poussey was incarcerated (so between 2011 and 2013), and, due to a failed furlough application, Poussey was never able to say goodbye in person.
Mrs. Washington is seen once in a flashback, and it is shown that her and Poussey had a very loving, close relationship. This is confirmed by Poussey who said that she loved her mom, and who is seen grieving her during Mother's Day at the prison ("Mother's Day").
- It's mentioned in "(Don't) Say Anything" that she has a Masters degree in Art History.